METHOD OF MANUFACTURING PAPER WITH UNBLEACHED CELLULOSE PULP SUSPENSION CONTAINING ORGANIC RESIDUES

Abstract

A method of making paper comprising adding to an aqueous suspension of cellulosic pulp slurry a polymer in the form of an inverse emulsion comprising a cationic poly N,N-(dialkylaminoalkyl) (meth)acrylamide or it's quaternates or salts, and dewatering the cellulose pulp slurry to form a paper or paperboard product, wherein the pulp slurry contains more than about 75 weight ppm of water soluble lignin based upon total pulp slurry weight, and wherein the polymer is added to the pulp slurry at a dosage of 0.001 to 1% by weight based upon cellulose pulp solids, and wherein the polymer optionally contains multi-functional monomer.

Claims

1. A method of making paper comprising adding to an aqueous suspension of cellulosic pulp slurry a polymer in the form of an inverse emulsion comprising a cationic poly N,N-(dialkylaminoalkyl) (meth)acrylamide or it's quaternates or salts; and dewatering the cellulose pulp slurry to form a paper or paperboard product, wherein the pulp slurry contains more than about 75 weight ppm of water-soluble lignin based upon total pulp slurry weight.

2. The method of claim 1 wherein the polymer further comprises multifunctional monomer.

3. The method of claim 2, wherein the polymer contains greater than about 25 molar ppm of multi-functional monomer based upon total monomer, and wherein the polymer has a G storage modulus of a 3% active polymer solution at a frequency of 40 rads/s of greater than 75 Pa.

4. The method of claim 2, wherein the polymer contains between 50 and 500 molar ppm of multi-functional monomer based upon total monomer.

5. The method of claim 1, wherein the cellulosic pulp slurry is unbleached.

6. The method of claim 1 wherein the pulp slurry contains more than about 100 weight ppm of water soluble lignin based upon total pulp slurry weight.

7. The method of claim 1 wherein the polymer comprises greater than 90% cationic monomer.

8. The method of claim 1 wherein the cationic poly N,N-(dialkylaminoalkyl) (meth)acrylamide or it's quaternates or its salts is formed from the polymerization of one or more cationic monomers wherein at least one cationic monomer is selected from the group consisting of N,N-dimethylaminoethylacrylamide, N,N-dimethylaminoethylmethacrylamide, N,N-dimethylaminopropylacrylamide, N,N-dimethylaminopropylmethacrylamide, N,N-diethylaminoethylacrylamide, N,N-diethylaminoethylmethacrylamide, N,N-diethylaminopropylacrylamide, N,N-diethylaminopropylmethacrylamide and the salts and quaternaries thereof; and/or combinations thereof.

9. The method of claim 1 wherein the cationic poly N,N-(dialkylaminoalkyl) (meth)acrylamide comprises N,N-dimethylaminopropylacrylamide or it's quaternates or its salts.

10. The method of claim 1 wherein the polymer further comprises a nonionic monomer selected from the group consisting of acrylamide; methacrylamide; N-alkylacrylamides, N,N-dialkylacrylamide, methyl acrylate; methyl methacrylate; acrylonitrile; N-vinyl methylacetamide; N-vinyl fromamide; N-vinyl methyl formamide; vinyl acetate; N-vinyl methyl formamide; vinyl acetate; N-vinyl pyrrolidone; hydroxyalky(meth)acrylates; and combinations thereof.

11. The method of claim 1 wherein the polymer comprises less than 10 mole % of non-ionic monomer, based upon total monomer, and wherein the resultant polymer contains more than 90 mole % cationic monomer.

12. The method of claim 1 wherein the polymer comprises less than 5 mole % of non-ionic monomer, based upon total monomer, wherein the resultant polymer contains more than 95 mole % cationic monomer.

13. The method of claim 1 wherein the polymer is added to the pulp slurry at a dosage of 0.001 to 1% by weight based upon cellulose pulp solids.

14. The method of claim 1 wherein the polymer has a 0.5% active UL viscosity of less than 15.0 cps.

15. The method of claim 1 wherein the polymer has a 0.5% active UL viscosity of less than 10.0 cps.

16. The method of claim 1 further comprising adding a siliceous material to the cellulosic pulp slurry.

17. The method of claim 16 wherein the siliceous material is selected from the group consisting of silica based particles, silica microgels, amorphous silica, colloidal silica, anionic colloidal silica, silica sols, silica gels, polysilicates, polysilicic acid, and combinations thereof.

18. The method of claim 1 wherein at least one additional coagulant or flocculant is added to the pulp slurry.

19. The method of claim 18 wherein the one additional coagulant or flocculant is water soluble.

20. The method of claim 1 wherein the cellulosic pulp slurry has less than 5% by weight filler based on weight of the cellulose pulp solids.

Description

EXAMPLES

[0057] The following examples show one method of making a cationic polymer using the inverse (water-in-oil) emulsion polymerization process. Additionally, the following examples illustrate the increased drainage performance of an unbleached pulp slurry containing organic and inorganic pulp mill residues resulting from adding at least one substantially cationic polymer to the pulp slurry. These examples are merely illustrative of the presently disclosed and/or claimed inventive concept(s) and are not to be construed as limiting the presently disclosed and/or claimed inventive concept(s) to the particular compounds, processes, conditions, or applications disclosed therein.

[0058] Examples 1-10. A sample of the polymer was prepared as described. An oil phase of paraffin oil (140 g, Conosol C170 oil, available from Calumet Specialty Products, Karns City, Pa.) and emulsification surfactants (15 g Hypermer 1031, Croda, New Castle, Del.) were charged to a suitable glass vacuum reaction flask equipped with an overhead 4 blade mechanical stirrer, heating mantle, thermometer, nitrogen sparge tube, vacuum pump, regulator, and distillate trap.

[0059] An aqueous phase was prepared separately which comprised 60 wt % dimethylaminopropyl acrylamide chloride solution in water (333.3 g), deionized water (61.16 g), and Versenex 80 (Dow Chemical) chelant solution (0.18 g). The aqueous phase was then adjusted to pH 5.0 with the addition of approximately 1.2 grams of concentrated sulfuric acid.

[0060] The aqueous phase was then charged to the oil phase at ambient temperature while being mixed with the mechanical stirrer, the emulsion was then mixed for an additional 10 minutes. Next, the mixture was homogenized with a Braun hand-held mixer for 30 seconds to obtain a stable water-in-oil emulsion. This emulsion was sparged with nitrogen for 60 minutes, while the temperature of the emulsion was increased to 61 C. The emulsion was continuously mixed during the process. Afterwards, the sparge was discontinued, the reactor was sealed, and a vacuum was applied to a level of 125 torr and water was distilled off to reduce the reactor temperature of 57 C.

[0061] The polymerization was initiated by adding 5 mls of a 1.5% solution of 2,2-azobis-(2,4-dimethylpentanenitrile) (V-65, Wako Chemicals, Richmond, Va.) in Conosol C170 oil, corresponding to 300 molar ppm of initiator based upon total moles of monomer. The reaction commenced as evidenced by an increase in temperature to 58 C. and the generation of distillate water. The reaction continued until the temperature decreased to 55 C. The vacuum was removed, a nitrogen sparge was applied, and the reaction was heated to 75 C. with the use of an external heating mantle. The reaction was then cooled to 45 C., and 0.61 grams of a 30% aqueous solution of sodium metabisulfite (Sigma Aldrich, Milwaukee, Wis.) was added. The batch was the cooled and a breaker surfactant comprising 10 grams of Genapol LA 070S (Clariant, Charlotte, N.C.) was added.

[0062] These acronyms will be utilized in the following examples: [0063] DIMAPAdimethylaminopropyl acrylamide [0064] DIMAPA-Qdimethylaminopropyl acrylamide chloride [0065] DIMAPMA-Qdimethylaminopropyl methacrylamide chloride [0066] ADAME-Q2-dimethylamino ethylacrylate chloride [0067] AMacrylamide [0068] MBAmethylenebisacrylamide [0069] MFMmulti-functional monomer [0070] Additional examples and comparative examples were prepared according to Example 1 with the following modifications:

TABLE-US-00001 TABLE 1 Monomer MFM Molar UL viscosity, G' Storage Modulus, Polymer Monomer Ratios MFM ppm 0.5%, cps 3% active, Pa Example 1 DIMAPA-Q 100 9.1 32.5 Example 2 DIMAPA 100 MBA 0.02 2.08 Example 3 DIMAPA 100 MBA 0.05 1.68 Example 4 DIMAPA-Q 100 MBA 0.02 4.33 102.8 Example 5 DIMAPA-Q 100 MBA 0.05 2.24 639.6 Example 6 DIMAPA-Q 100 MBA 0.1 1.76 1190.6 Example 7 DIMAPA-Q 100 MBA 0.005 14 Example 8 DIMAPA-Q 100 MBA 0.01 10 Example 9 DIMAPMA-Q 100 6.69 Example 10 DIMAPMA-Q 100 MBA 0.02 2.54 Comparative Example 1 ADAME-Q/AM 10/90 MBA 0.05 1.49 Comparative Example 2 ADAME-Q/AM 10/90 MBA 0.1 1.39 MFMmultifunctional monomer MFM Molar ppmmolar ppm of MFM based upon total moles of monomer

[0071] A series of drainage tests were conducted to evaluate the performance of the polymer samples from Table 1. A thick stock machine chest pulp sample from a US southern virgin linerboard manufacturer was utilized to prepare a test furnish in a series of drainage tests; the data are provided below in Tables 2, 3, and 4. The thick stock consistency was in the range of 3.6 weight % and the pH was in the range of 9-10. The consistency was diluted to 0.8%, the pH was adjusted to 5.0 with concentrated sulfuric acid, 0.15% sodium sulfate was added to achieve a total conductivity of 2500 S/cm, and Indulin C (Mead Westvaco, North Charleston, S.C.) was added to achieve a total water soluble lignin level of 349 weight ppm based on total pulp slurry weight. The level of water soluble lignin in all subsequent examples are weight ppm based upon total pulp slurry weight. The drainage activity of the invention was determined utilizing a Dynamic Drainage Analyzer (DDA), test equipment available from AB Akribi Kemikonsulter, Sundsvall, Sweden. The test device applies a 300 mbar vacuum to the bottom of the separation medium. The device electronically measures the time between the application of vacuum and the vacuum break point, i.e. the time at which the air/water interface passes through the thickening fiber mat. It reports this value as the drainage time. A lower drainage time is preferred. 500 mls of stock is added to the DDA and the drainage test is conducted at a total instrument vacuum of 300 mbar pressure.

[0072] The level of soluble lignin was determined by measuring the absorbance of a filtered furnish sample at a wavelength of 280 nm using an Ocean Optics (Dunedin, Fla.) USB 4000 spectrometer. The quantitative level of lignin was determined from a calibration curve, derived by measuring the absorbance at 280 nm of a series of Indulin C kraft lignin at varying concentrations ranging from 50 to 1000 weight ppm.

[0073] The treatment dosages in all experiments were 15 pounds per ton aluminum sulfate dodecahydrate (Delta Chemical, Baltimore, Md.), then followed by one of the following drainage aid treatments from Table 1. This series of experiments also utilized a commercial drainage aid Hercobond 6950 (Solenis, Wilmington, Del.) a modified polyvinylamine. Ten seconds mix time was utilized between additives, and after the last additive before commencing the drainage test. The dosages are all polymer product based upon dry pulp. The reported drainage times are the average of 3 test replicates.

TABLE-US-00002 TABLE 2 Drain #/T Time, % Polymer (active) s Change None 0 9.53 0 Example 1 2 7.67 19.50 Example 2 2 7.34 22.96 Example 3 2 7.62 19.99 Comparative Example 1 2 8.57 10.09 Comparative Example 2 2 9.08 4.67 Hercobond 6950 2 10.20 7.00

TABLE-US-00003 TABLE 3 #/T Drain % Polymer (active) Time, s Change None 0 7.84 Example 1 2 7.44 5.10 Example 2 2 7.03 10.29 Example 3 2 7.24 7.56 Example 4 2 6.41 18.24 Example 5 2 6.85 12.63

TABLE-US-00004 TABLE 4 #/T Drain % Polymer (active) Time, s Change None 0 7.77 0 Example 2 2 6.43 17.20 Example 3 2 6.78 12.78 Example 6 2 6.46 16.82 Comparative Example 1 2 7.17 7.72 Comparative Example 2 2 6.79 12.57

[0074] The data demonstrate better (lower drainage times) drainage provided by the inventive polymer compared to conventional ADAM-E/AM drainage aid polymers. The commercial drainage aid Hercobond 6950 product was not effective in this high lignin environment. An improvement is also noted with Examples 2, 4, 5, and 6 compared to Example 1 when modified with multi-functional monomer MBA.

[0075] Another series of experiments was conducted to illustrate the negative effect of soluble lignin on the performance of conventional drainage aids. The same thick stock in the above examples was utilized, but was washed repeatedly with deionized water to remove the soluble lignin from the pulp slurry. A fabric comprising 200 thread count was utilized so no fiber fines were removed from the pulp slurry. The furnish was then prepared as above, but no lignin was added initially. The soluble lignin was measured at 30 weight ppm. A first series of drainage studies were conducted, then the stock was modified by the addition of 270 weight ppm of Indulin AT (Mead Westvaco, North Charleston, S.C.) for a total soluble lignin content of 300 weight ppm. The data in Table 5 illustrate the positive drainage response from the commercial drainage aid Hercobond 6950 in the low lignin substrate. The drainage of the commercial product was negatively affected by the increase of lignin from 30 to 300 weight ppm. This was also evident in Table 2, where the Hercobond 6950 was ineffective in the furnish containing 350 weight ppm of water soluble lignin.

TABLE-US-00005 TABLE 5 Drain #/T Lignin, Time, % Polymer (active) ppm s Change None 0 30 2.92 Hercobond 6950 2 30 2.50 14.40 None 0 300 3.28 Hercobond 6950 2 300 3.53 7.61

[0076] Another series of drainage studies were conducted utilizing stock from a second US southern virgin linerboard manufacturer. Samples of refined machine chest thick stock and tray water were utilized to prepare a test furnish to replicate the actual papermachine conditions. The final consistency was 0.4%, the pH was 5.2, the conductivity was 3250 S/cm, and the water soluble lignin was 99 weight ppm. The same drainage methods for the DDA in the previous samples were utilized. This series of experiments was conducted with 9 pounds of alum per ton of dry furnish pulp. The data are presented in Table 6, and demonstrate good drainage performance from the inventive polymers.

TABLE-US-00006 TABLE 6 #/T Drain % Polymer (active) Time, s Change None 0 12.39 Example 1 1 10.26 17.20 Example 4 1 11.84 4.39 Example 5 1 11.54 6.86 Example 7 1 11.49 7.21

[0077] Another series of drainage studies were conducted utilizing stock from a third US southern virgin linerboard manufacturer. Samples of refined machine chest thick stock and tray water were utilized to prepare a test furnish to replicate the actual papermachine conditions. The final consistency was 0.6%, the pH was 5.0, the conductivity was 2250 S/cm, and the soluble lignin was 30 weight ppm. The same drainage methods for the DDA in the previous samples were utilized. This series of experiments was conducted with 18 pounds per ton of alum. This series of experiments also utilized a commercial drainage aid Hercobond 6950 (Solenis, Wilmington, Del.) a modified polyvinylamine. The data are presented in Table 7, and demonstrate good drainage performance from the inventive polymers compared to the commercial drainage aid, which did not provide a drainage response above the untreated system.

TABLE-US-00007 TABLE 7 #/T Drain % Polymer (active) Time, s Change None 0 16.19 Example 1 1 14.85 8.26 Example 4 1 15.79 2.49 Example 5 1 16.98 4.85 Example 7 1 15.11 6.67 Example 8 1 15.64 3.40 HercoBond 6950 2 16.04 0.93

[0078] Another series of drainage studies were conducted utilizing stock from a fourth US southern virgin linerboard manufacturer. Samples of refined machine chest thick stock and tray water were utilized to prepare a test furnish to replicate the actual papermachine conditions. The final consistency was 0.6%, the pH was 4.2, the conductivity was 3050 S/cm, the water soluble lignin was 325 weight ppm. The same drainage methods for the DDA in the previous samples were utilized. This series of experiments was conducted with 19 pounds per ton of alum. The polymer dosages are based upon an as received polymer basis. The data are presented in Table 8, and a positive drainage response was provided from polymer Examples 1 and 4 compared to the untreated system.

TABLE-US-00008 TABLE 8 #/T (as Drain % Polymer product) Time, s Change None 21.0 0 Example 1 1 14.0 33.3 Example 1 2 12.3 41.4 Example 4 1 19.0 9.5 Example 4 2 19.0 9.5

[0079] Another series of drainage studies were conducted utilizing stock from the third US southern virgin linerboard manufacturer (Table 7), where the effect of lignin concentration on the drainage of the inventive polymers was evaluated. The level of lignin in the furnish was initially 30 weight ppm, and was increased by the addition of the noted level of kraft lignin (Indulin C, Mead Westvaco, North Charleston, S.C.) or lignosulfonate (Borrosperse NA, LignoTech USA, Bridgewater, N.J.). Samples of refined machine chest thick stock and tray water were utilized to prepare a test furnish to replicate the actual papermachine conditions. The initial consistency was 0.4%, the pH was 5.0, the conductivity was 2320 S/cm. After each addition of lignin, the pH was adjusted to 5.0. The same drainage methods for the DDA in the previous samples were utilized. This series of experiments was conducted with 18 pounds per ton of alum. The data are presented in Table 9. The drainage of Example 4 modified with 200 molar ppm of MBA based upon total monomer becomes faster than the control. Example 4 maintains a positive drainage response upon the addition of lingo-sulfonate, a highly anionic lignin.

TABLE-US-00009 TABLE 9 Kraft Ligno- #T Lignin, sulfonate, Drain % Polymer (active) ppm ppm time Change None 0 30 0 13.1 0.0 Example 4 1 30 0 13.0 0.7 None 0 130 0 14.8 0.0 Example 4 1 130 0 13.2 10.7 None 0 330 0 19.0 0.0 Example 4 1 330 0 17.7 6.8 None 0 330 100 13.4 0.0 Example 4 1 330 100 12.9 3.8

[0080] Another series of drainage studies were conducted utilizing the modified stock from the first US southern virgin linerboard manufacturer (Tables 2, 3, and 4). In this series of experiments homo-polymers of dimethylaminopropyl methacrylamide chloride were utilized. The data are presented in Table 10, and illustrate a positive drainage response using linear and cross-linked polymers prepared with this monomer.

TABLE-US-00010 TABLE 10 #/T Drain % Polymer (active) Time, s Change None 0 8.79 Example 9 1 8.33 5.20 Example 10 1 7.43 15.44